Describing the full functionality of Praat would take too long, but all you really need to know is that it can be an invaluable tool for speech manipulation. It enables you to analyze and synthesize speech, using a vast range of specialized tools. The program can also draw high quality pictures, to illustrate your work, which you can use in articles or theses.

Praat is free and open source and it is available for multiple operating systems, like Windows, Mac OS X, Linux, FreeDB and others. It comes as a single binary file, which you only need to extract and run. You can also take it with you on a portable storage device and use the application on other machines.

When launched, Praat will display two windows, one for the main input and one for displaying various output images. The input window has a simple appearance, but once you import an audio file, you will find a vast range of options and you may need some time to figure out where to start. Fortunately, you can find a well structured manual, as well as a few tutorials on the software's website.

Voice recordings can be loaded in a list, on the left side of the main interface. Once the file is imported, a large number of options will be made available next to the list, which allow you to perform numerous operations, from simply playing the recording to analyzing or modifying. You can bring up spectrograms on separate windows on which you can view pulses, analyze the pitch and intensity and much more.

When you make a modification, like converting to mono or stereo, filtering sounds and so on, the modification won't be applied directly on the original file. Instead, the software will create a modified copy and it will display it in the same list. Depending on the performed operation, you will find different options when you select a modified copy.

Pros: You can analyze voice recordings and manipulate them. The software places a huge amount of useful tools at your disposal.

Cons: It may take some time to learn the program's controls.

Anything you want to know about a voice sample can be obtained in an efficient manner with Praat.